Can I upgrade someone else's avios booking?
My gf is booking a RFS award seat for her parents, DME-LHR, if I notice space in J can I call up and use my avios to upgrade them? She'll be in the UK and me in the US, so I wont be able to pass the phone over for her to give the ok for me to interfere with her booking, so just wondering if the agent will even discuss the booking with me?